The present invention relates to a push switch provided, for example, in a vehicle or the like.
Japanese Patent Laid-Open Publication No. 2006-100013 describes a vehicle switch comprising a switch main body, which is held in an external member on the vehicle, and a button, which is provided in an opening in the external member, and is linked to the switch main body. In this vehicle switch, the button comprises a base made from a rubber material, which is provided in the opening in the external member, and linked to the switch main body, and a hard, decorative member, which covers the outside of the base.
With the vehicle switch described in Japanese Patent Laid-Open Publication No. 2006-100013, the decorative member constitutes a part of the exterior design of the external member on the vehicle, and various types of decoration can be provided on the decorative member, allowing for more freedom in the decoration of the button and better design characteristics for the button.
Japanese Patent Laid-Open Publication No. 2009-104804 describes a mounting structure for a pushbutton switch comprising: a switch mounting device provided with a switch exposure opening; and a pushbutton switch, in which a switch main body, which is covered and sealed by an elastic seal material, is operated by a pushbutton part that is exposed via the switch exposure opening when fastened in the switch mounting device. In this mounting structure, the pushbutton part is formed as a cap member, which is formed from a hard material, and is connected to the elastic seal material in an easily detachable manner, detachment of the cap member being regulated by way of a stopper part on this cap member being constrained by the back of the circumferential edge of the switch exposure opening in the switch mounting device.
With the pushbutton switch mounting structure described in Japanese Patent Laid-Open Publication No. 2009-104804, it is possible to flexibly support a variety of color specifications and the like, because the pushbutton part can be easily detached. Furthermore, the pushbutton part will not detach when the switch mounting device is mounted.
Japanese Patent Laid-Open Publication No. 2010-244825 describes a push switch comprising: a soft cylindrical inner button having an outer flange; a hard button fastened to the inner button so as to cover the inner button; a switch board mounted in an opening in the inner button; a switch arranged within the inner button; and a case fastened to the side wall of the inner button. In this push switch, the button has a peripheral sidewall and a top operation wall, an overhanging part being provided at the end of the peripheral sidewall. Furthermore, the overhanging part is arranged so as to face an inner flange provided on the case, and so as to leave a gap between this and the outer flange on the inner button, so that when the switch is turned on by pushing the button and elastically deforming the inner button, the overhanging part comes into contact with the outer flange.
With the push switch described in Japanese Patent Laid-Open Publication No. 2010-244825, because the hard button is arranged so as to cover the soft inner button, the inner button can be protected, even if it is struck by fingernails or the like. Furthermore, the switch is not subjected to excessive pushing forces because, when the switch is turned on, the overhanging part on the button makes contact with the outer flange on the inner button, so that the pushing force on the button is received by the inner flange on the case.
However, with the vehicle switch described in Japanese Patent Laid-Open Publication No. 2006-100013, because the base and the decorative member are connected by fitting a projection provided on the decorative member in a hole provided in the base, which is made from the rubber material, the seal characteristics are readily degraded and there is a risk of water penetrating into the space in which the switch main body is disposed. Furthermore, with the vehicle switch described in Japanese Patent Laid-Open Publication No. 2006-100013, if a large pushing force acts on the button, the thin flexible portion provided in the base, which is made from the rubber material, is unduly stretched, such that there is a risk of the base itself being damaged.
With the pushbutton switch mounting structure described in Japanese Patent Laid-Open Publication No. 2009-104804, the seal characteristics are good because the switch main body is covered and sealed by the elastic seal material. However, because the structure is such that when the pushbutton part is push-operated, a portion of the soft pushbutton part is trapped between the pushbutton part that is made from the hard material and the switch case that is made from the hard material, there is a risk that the portion that is trapped between the pushbutton part and the switch case will be damaged by repeated push-operations and that the seal produced by the elastic seal member will be broken.
With the push switch described in Japanese Patent Laid-Open Publication No. 2010-244825, because the structure is such that, when the button is push-operated, the outer flange on the soft inner button is trapped between the overhanging part on the button, which is made from the hard material, and the inner flange on the case, there is a risk that the outer flange will be damaged by the repeated push-operations and that the seal produced by the inner button will be broken.